A white Christmas is a Christmas with the presence of snow, either on Christmas Eve or on Christmas Day, depending on local tradition. The phenomenon is most common in the northern countries of the Northern Hemisphere. This is because December is at the beginning of the Southern Hemisphere summer, and so white Christmases there are extremely rare - with the exception being Antarctica, the Southern Alps of New Zealand's South Island, and parts of the Andes in South America as well as the southern tip of the continent, in places like Ushuaia, Argentina.
The climate of Chicago is classified as hot-summer humid continental with hot humid summers and cold, occasionally snowy winters. All four seasons are distinctly represented: Winters are cold and often see snow with below 0 Celsius temperatures and windchills, while summers are warm and humid with temperatures being hotter inland, spring and fall bring bouts of both cool and warm weather and fairly sunny skies. Annual precipitation in Chicago is moderate and relatively evenly distributed, the driest months being January and February and the wettest July and August. Chicago's weather is influenced during all four seasons by the nearby presence of Lake Michigan.
The geography of Toronto, Ontario, covers an area of 630 km2 (240 sq mi) and is bounded by Lake Ontario to the south; Etobicoke Creek, Eglinton Avenue, and Highway 427 to the west; Steeles Avenue to the north; and the Rouge River and the Scarborough–Pickering Townline to the east. In addition to Etobicoke Creek and the Rouge River, the city is trisected by two minor rivers and their tributaries, the Humber River in the west end and the Don River east of downtown. Both flow southward to Lake Ontario at Humber Bay and Toronto Harbour respectively, which are part of the longer Waterfront, as well as Etobicoke Creek and the Rouge River.
The climate of Minneapolis–Saint Paul is the long term weather trends and historical events of the Minneapolis–Saint Paul metropolitan area in east central Minnesota. Minneapolis and St. Paul, together known as the Twin Cities, are the core of the 15th largest metropolitan area in the United States. With a population of 3.6 million people, the region contains approximately 60% of the population of Minnesota. Due to its location in the northern and central portion of the U.S., the Twin Cities has the coldest average temperature of any major metropolitan area in the nation. Winters are very cold, summer is warm and humid, snowfall is common in the winter and thunderstorms with heavy rainfall occur during the spring, summer and autumn. Though winter can be cold, the area receives more sunlight hours in mid-winter than many other warmer parts of the country, including all of the Great Lakes states, the Pacific Northwest, parts of the South, and almost all of the Northeast. Unless otherwise indicated, all normals data presented below are based on data at Minneapolis/St. Paul International Airport, the official Twin Cities climatology station, from the 1981−2010 normals period.
Milwaukee has a humid continental climate, with four distinct seasons and wide variations in temperature and precipitation in short periods of time. The city's climate is also strongly influenced by nearby Lake Michigan, which creates two varying climates within the Milwaukee area. The urban heat island effect also plays a role in the city's climate, insulating it from winter cold, but keeping it cooler in spring and summer.
Yarmouth, officially named the Municipality of the District of Yarmouth, is a district municipality in Yarmouth County, Nova Scotia, Canada. Statistics Canada classifies the district municipality as a municipal district.
Minnesota has a humid continental climate, with hot summers and cold winters. Minnesota's location in the Upper Midwest allows it to experience some of the widest variety of weather in the United States, with each of the four seasons having its own distinct characteristics. The area near Lake Superior in the Minnesota Arrowhead region experiences weather unique from the rest of the state. The moderating effect of Lake Superior keeps the surrounding area relatively cooler in the summer and warmer in the winter, giving that region a smaller yearly temperature variation. On the Köppen climate classification, much of the southern third of Minnesota—roughly from the Twin Cities region southward—falls in the hot summer zone (Dfa), and the northern two-thirds of Minnesota falls in the warm summer zone (Dfb).
The climate of Houston is classified as a humid subtropical climate, with tropical influences. August normally ranks as the warmest month at an average temperature of 95 °F (35 °C) and January the coldest month at an average temperature of 63 °F (17 °C).
North Dakota's climate is typical of a continental climate with cold winters and warm-hot summers. The state's location in the Upper Midwest allows it to experience some of the widest variety of weather in the United States, and each of the four seasons has its own distinct characteristics. The eastern half of the state has a humid continental climate with warm to hot, somewhat humid summers and cold, windy winters, while the western half has a semi-arid climate with less precipitation and less humidity but similar temperature profiles. The areas east of the Missouri River get slightly colder winters, while those west of the stream get higher summer daytime temperatures. In general, the diurnal temperature difference is prone to be more significant in the west due to higher elevation and less humidity.
Climate in Canada varies widely from region to region. In many parts of the country, particularly in the interior and Prairie provinces, winters are long, very cold, and feature frequent snow. Most of Canada has a continental climate, which features a large annual range of temperatures, cold winters, and warm summers. Daily average temperatures are near −15 °C (5 °F), but can drop below −50 °C (−58 °F) with severe wind chills. In non-coastal regions, snow can cover the ground for almost six months of the year, while in parts of the north snow can persist year-round. Coastal British Columbia has a more temperate climate, with a mild and rainy, cloudy winter. On the east and west coasts, average high temperatures are generally in the low 20s °C, while between the coasts, the average summer high temperature ranges from 25 to 30 °C, with temperatures in some interior locations occasionally exceeding 40 °C (104 °F).
The climate of Georgia is a humid subtropical climate, with most of the state having short, mild winters and long, hot summers. The Atlantic Ocean on the east coast of Georgia and the hill country in the north impact the state's climate. Also, the Chattahoochee River divides Georgia into separate climatic regions with the mountain region to the northwest being cooler than the rest of the state; the average temperatures for the mountain region in January and July are 39 °F (4 °C) and 78 °F (26 °C) respectively. Winter in Georgia is characterized by mild temperatures and little snowfall around the state, with the potential for snow and ice increasing in the northern parts of the state. Summer daytime temperatures in Georgia often exceed 95 °F (35 °C). The state experiences widespread precipitation. Tornadoes and tropical cyclones are common.
Montreal is the second largest city in Canada and the largest city in the province of Quebec, located along the Saint Lawrence River at its junction with the Ottawa River. The city is geographically constrained, with the majority on the Island of Montreal in the Hochelaga Archipelago, and has several prominent features, including the eponymous Mount Royal. The region experiences four distinct seasons and is classified as a humid continental climate, with very cold and snowy winters and warm and humid summers.
The December 2008 North American snowstorms were a series of snowstorms that struck across Canada and the US. The snowstorms caused snow to fall across Canada and many parts of the United States, and broke records for the amount of snow accumulated in many cities on Christmas Day.
The climate of Allentown, Pennsylvania is classified as a humid continental climate. Allentown's warmest month is July with a daily average temperature of 74.7 °F (23.7 °C) and the coldest month being January with a daily average of 29.4 °F (−1.4 °C). The average precipitation of Allentown is 45.35 inches (1,152 mm) per year.
The winter of 2010–2011 in Europe began with an unusually cold November caused by a cold weather cycle that started in southern Scandinavia and subsequently moved south and west over both Belgium and the Netherlands on 25 November and into the west of Scotland and north east England on 26 November. This was due to a low pressure zone in the Baltics, with a high pressure over Greenland on 24 November, and ended on 3 May 2011 in Poland.
The 2014–15 North American winter was frigid and prolifically wintry, especially across the eastern half of North America in the months of January–March. The season began early, with many places in North America experiencing their first wintry weather during mid-November. A period of below-average temperatures affected much of the contiguous United States, and several records were broken. An early trace of snowfall was recorded in Arkansas. There were greater accumulations of snow across parts of Oklahoma as well. A quasi-permanent phenomenon referred to as the polar vortex may have been partly responsible for the cold weather. Temperatures in much of the United States dropped 15 to 35 °F below average by November 19, following a southward "dip" of the polar vortex into the eastern two-thirds of the country. The effects of this dip were widespread, bringing about temperatures as low as 28 °F (−2 °C) in Pensacola, Florida. Following a significant snowstorm there, Buffalo, New York received several feet of snow from November 17–21. In addition, significant winter weather occurred throughout the season, including a major blizzard that struck the Northeastern United States at the end of January, another blizzard that affected much of the Northern United States days later in early February, and several significant snow events paired with very frigid temperatures for much of February.
The 2015–16 North American winter was not as frigid across North America and the United States as compared to the 2013–14 and 2014–15 winters. This was mainly due to a strong El Niño, which caused generally warmer-than-average conditions. However, despite the warmth, significant weather systems still occurred, including a snowstorm and flash flooding in Texas at the end of December and a large tornado outbreak at the end of February. The main event of the winter season, by far and large, was when a crippling and historic blizzard struck the Northeastern United States in late January, dumping up to 3 feet of snow in and around the metropolitan areas. Several other smaller snow events affected the Northeast as well, but for the most part the heaviest snowstorms and ice stayed out further west, such as a severe blizzard in western Texas in late December, and a major late-season snowstorm in Colorado in mid-April.
In late January 2019, a severe cold wave caused by a weakened jet stream around the Arctic polar vortex hit the Midwestern United States and Eastern Canada, killing at least 22 people. It came after a winter storm brought up to 13 inches (33 cm) of snow in some regions from January 27–29, and brought the coldest temperatures in over 20 years to most locations in the affected region, including some all-time record lows. In early February, a concentration of Arctic air colloquially referred to as the "polar vortex" moved west, and became locked over Western Canada and the Western United States. As a result, February 2019 was among the coldest and snowiest on record in these regions. In early March, the cold once again shifted east, breaking records in many areas. In mid-March, the cold wave finally retreated, but combined with above-average temperatures, precipitation, and a deep snowpack, widespread flooding ensued in the Central US.
According to the Köppen climate classification, the climate of New York City is humid subtropical (Cfa), with parts of the city transitioning into a humid continental climate. (Dfa). The city experiences long, hot, humid summers with frequnet late day thundershowers, and moderately cold winters, with occasional snow or a mix of snow and rain. As it is much more geographically southern, it is usually warmer in winter than in Upstate New York. Also, New York's enormous population, human activity, and vast amounts of large buildings and streets, which absorb sunlight during the day, contribute significantly to the urban heat island effect.
The climate of Seattle is temperate, classified in the warm-summer (in contrast to hot-summer) subtype of the Mediterranean zone by the most common climate classification although some sources put the city in the oceanic zone. It has cool, wet winters and warm, dry summers, covering characteristics of both. The climate is sometimes characterized as a "modified Mediterranean" climate because it is cooler and wetter than a "true" Mediterranean climate, but shares the characteristic dry summer and the associated reliance upon cooler-season precipitation. The city is part of USDA hardiness zone 9a, with surrounding pockets falling under 8b.
